Alright, so my acne is what I believe to be moderate. I don't break out very much anymore, but when I do, it's a big cyst farm on my face! 
I can go most days without wearing makeup, but some days, I just like to have a little coverage. When I was younger, I thought I needed the heaviest of the heavy, but I've grown to realize that sheer-medium coverage is all I Need. I've been experimenting with bb creams lately and have not been impressed at all! What are some ingredients in cosmetics that go directly onto skin (foundation, powders, tinted moisturizer, etc.) that I should avoid. My skin is extremely sensitive so all of the advice you awesome folks can give me will be much appreciated! By me AND my face. 
BB creams unfortunately break a lot of people out as they sink into the pores more :/
First off I would say that you should apply a silicone based primer under ANY makeup you wear to create a barrier which prevents any irritating products from getting into the skin.
In terms of ingredients to avoid, I am a crazy non comedogenic freak. I avoid ANYTHING which contains pore clogging or irritating ingredients.
The worst things in cosmetics that make me break out are:
- Stearic Acid
- Cetyl / Cetearyl / Cetostearyl Alcohol
- Any types of Palm oil such as Ethylhexyl Palmitate or Palm Kernel Oil
- Coconut Oil
- Acohol denat (for your sensitive skin)
- Isopropyl Isostearate (one of the worst and most common offenders!)
- Isopropyl Myristate
- Myristyl Myristate
- Synthetic Lanolin
Those are just the main ones in makeup and moisturisers which are very bad. There are hundreds more but are far less common.
As a rule of thumb I generally avoid anything with the word alcohol or "stearic/stearate/stearyl" in it as they tend to be the ones that break me out most.
You can find a full list of ingredients that can cause/aggrivate acne here: http://www.zerozits.com/Articles/acnedetect.htm#inglist
Since cutting out ALL comedogenic ingredients from my skincare routine, I have noticed my skin has cleared up by about 40% and that's only been over the course of a week.
Don't trust packaging saying that the product is Non-Comedogenic, because it nearly always contains an ingredient on that list.
It is often said that one or two ingredients from the list are okay and will not aggrivate acne, however I prefer to play it safe and avoid anything with it.
The only ingredient that is on that list that I DO use is Jojoba oil because it is widely disputed wether or not it is comedogenic, however it does not cause me any problems and actually reduces my acne + inflammation. You'll see that it is rated 0-2 on the scale for that reason.
If the comedogenic rating is below 2 then it should be okay as long as it's towards the end of the ingredients list.
P.S if you can't find the ingredients for a certain product anywhere then search it on drugstore.com as you can view the ingredients for almost everything there 
Sorry for the long post!
Our makeup tips: http://www.acne.org/faq.html#cosmetics
and http://www.acne.org/blog/2009/04/27/makeup-if-you-must/
Our list of problematic ingredients: http://www.acne.org/comedogenic-list.html
Hope that helps!